ION TEST T2
Section 1: Multiple Choice (10 marks)
Circle the correct answer.
1. What is an ion?
- a) A neutral atom
- b) An atom that has gained or lost electrons
- c) An atom with a full outer shell
- d) A radioactive atom
2. Which of the following is a polyatomic ion?
- a) Cl⁻
- b) Mg²⁺
- c) OH⁻
- d) K⁺
3. A cation is:
- a) A positively charged ion
- b) A negatively charged ion
- c) A neutral atom
- d) An atom with extra neutrons
4. Which of the following elements forms a 2+ ion?
- a) Sodium
- b) Oxygen
- c) Calcium
- d) Fluorine
5. What is the formula for the sulfate ion?
- a) SO₃²⁻
- b) SO₄²⁻
- c) SO₄⁻
- d) SO₂²⁻
6. What is the charge on an aluminium ion?
- a) 1⁺
- b) 2⁺
- c) 3⁺
- d) 3⁻
7. What happens when a non-metal becomes an ion?
- a) It loses electrons
- b) It becomes neutral
- c) It gains electrons
- d) It evaporates
8. Which group in the periodic table forms -1 ions?
- a) Group 1
- b) Group 2
- c) Group 17
- d) Group 18
9. Which of the following formulas is correct?
- a) NaCl₂
- b) CaO
- c) K₂O₂
- d) MgCl
10. What is the correct formula for barium sulfate?
- a) Ba(SO₄)₂
- b) Ba₂SO₄
- c) BaSO₄
- d) BaSO₃
Section 2: Convert Names to Formulas (20 marks)
Write the correct chemical formula for each compound. (1 mark each)
- Sodium chloride: NaCl
- Magnesium oxide: MgO
- Calcium nitrate: Ca(NO₃)₂
- Aluminium sulfate: Al₂(SO₄)₃
- Ammonium chloride: NH₄Cl
- Potassium permanganate: KMnO₄
- Lithium phosphate: Li₃PO₄
- Iron (III) oxide: Fe₂O₃
- Zinc hydroxide: Zn(OH)₂
- Barium carbonate: BaCO₃
- Copper (II) nitrate: Cu(NO₃)₂
- Sodium sulfate: Na₂SO₄
- Lead (II) iodide: PbI₂
- Silver nitrate: AgNO₃
- Calcium hydroxide: Ca(OH)₂
- Aluminium carbonate: Al₂(CO₃)₃
- Magnesium sulfate: MgSO₄
- Ammonium phosphate: (NH₄)₃PO₄
- Iron (II) sulfide: FeS
- Potassium dichromate: K₂Cr₂O₇
Section 3: Convert Formulas to Names (20 marks)
Write the correct name for each ionic or polyatomic compound. (1 mark each)
- NaCl: Sodium chloride
- MgO: Magnesium oxide
- Ca(NO₃)₂: Calcium nitrate
- Al₂(SO₄)₃: Aluminium sulfate
- NH₄Cl: Ammonium chloride
- KMnO₄: Potassium permanganate
- Li₃PO₄: Lithium phosphate
- Fe₂O₃: Iron (III) oxide
- Zn(OH)₂: Zinc hydroxide
- BaCO₃: Barium carbonate
- Cu(NO₃)₂: Copper (II) nitrate
- Na₂SO₄: Sodium sulfate
- PbI₂: Lead (II) iodide
- AgNO₃: Silver nitrate
- Ca(OH)₂: Calcium hydroxide
- Al₂(CO₃)₃: Aluminium carbonate
- MgSO₄: Magnesium sulfate
- (NH₄)₃PO₄: Ammonium phosphate
- FeS: Iron (II) sulfide
- K₂Cr₂O₇: Potassium dichromate
Section 4: Write Formulas from Names (10 marks)
Write the correct chemical formula for each compound, using the same style as: E.g.: Manganese hydroxide → Mn(OH)₂ (1 mark each)
- Iron (III) nitrate → Fe(NO₃)₃
- Zinc carbonate → ZnCO₃
- Calcium hydroxide → Ca(OH)₂
- Aluminium phosphate → AlPO₄
- Copper (II) sulfate → CuSO₄
- Potassium permanganate → KMnO₄
- Ammonium sulfate → (NH₄)₂SO₄
- Magnesium nitrate → Mg(NO₃)₂
- Barium chromate → BaCrO₄
- Lead (II) bromide → PbBr₂
Section 5: Ion Questions (10 marks)
Answer the following questions in 1–2 sentences each. (1 mark each)
1. What is the difference between a cation and an anion? A cation is a positively charged ion (lost electrons), while an anion is negatively charged (gained electrons).
2. How is a calcium ion (Ca²⁺) formed from a neutral atom? A calcium atom loses two electrons to form a Ca²⁺ ion.
3. Why do non-metals tend to gain electrons when forming ions? Non-metals gain electrons to achieve a full outer shell like noble gases.
4. Explain why ionic compounds can conduct electricity when dissolved in water. Ionic compounds dissociate into ions in water, which allows them to conduct electricity.
5. What type of bonding exists in ionic compounds? Ionic bonding occurs between metals and non-metals, involving transfer of electrons.
6. Why don’t noble gases usually form ions? Noble gases already have full outer shells, so they do not need to gain or lose electrons.
7. What happens to electrons in the formation of an ionic bond? Electrons are transferred from the metal to the non-metal.
8. Why is the correct formula for magnesium chloride MgCl₂, not MgCl? Magnesium has a 2+ charge, and each chloride has a 1− charge, so two Cl⁻ ions are needed: MgCl₂.
9. What makes polyatomic ions different from simple ions? Polyatomic ions are made of two or more atoms that act as a single charged unit.
10. What charge would a sulfur ion have, and why? Sulfur would form an S²⁻ ion by gaining two electrons to fill its outer shell.